From a distance, Don Quixote sees a knight on a dappled steed wearing a golden, glistening helmet. As they approach, Sancho remarks that it is indeed a person on a gray ass wearing something like a barber's basin on his head. "Nonsense," says the Don, "That is a knight wearing Mambrino's helmet [Mambrino was a Saracen deprived by Don Rinaldo of his golden helmet] and I shall deal with him while you wait here." Sancho is right, of course, for the traveling barber has placed his bronze basin over his new hat to protect it from the rain. Don Quixote charges his adversary, and the poor barber throws himself to the ground to avoid being speared by the lance. He then runs through the fields as fast as possible. Don Quixote wins the helmet and Sancho exchanges the trappings of his ass for the superior packsaddle of the barber's mule. Pleasantly discoursing, the two well-furnished companions ride contentedly along.
The next adventure begins when Don Quixote stops some guards who are taking twelve prisoners in a chain gang to the place where they will serve as galley slaves. After listening to the story of each prisoner, the knight demands that the guards set them free for "'tis a hard case to make slaves of men whom God and nature made free." The guard refuses, and while Don Quixote fights with him, the prisoners use the opportunity to struggle out of their chains. When the guards are all subdued, Don Quixote demands of each prisoner that he present himself before the Lady Dulcinea and describe how he gained his freedom. The ringleader, a notorious rogue named Gines de Passamonte, realizes that the knight is mad, and he signals to his companions. All the prisoners throw stones at their liberator until he is knocked down. Stealing whatever they can find, they swiftly scatter and disappear along their separate ways.
Sancho, afraid that the police force of the Holy Brotherhood would search for the man who freed the king's prisoners, suggests they go through the Sierra Morena to discourage pursuit. The ringleader of the prisoners, Gines de Passamonte, is also hiding out in these mountains. When he sees his chance, he steals Sancho's beloved ass Dapple, leaving the squire brokenhearted. Sancho is cheered, however, when his master finds a portmanteau lying on the path that contains 200 gold crowns; he gives it all to his squire, taking sole interest in the poem enclosed in the briefcase. Further along, they see a discarded saddle and then the corpse of a mule. Some goatherds tell them the story that clears up the mystery. A well-born youth has come to do penance for a number of sins. He wanders around in the wilderness, alternating moods of lucidity with fits of insanity, gaining nourishment from the woods or from the kindness of the goatherds. Don Quixote vows to find the young man and assist him in his distress. Cardenio himself appears, and the knight greets him with an earnest embrace, as if the stranger were long familiar to him.
The young man, or the Knight of the Wood, as Cervantes calls him, tells Don Quixote of his misfortunes. The son of an Andalusian gentleman, he was about to become betrothed to his beloved Lucinda, a beautiful, discreet maiden of similar background to himself. His father, however, sent Cardenio to live at the Duke's house and become a companion to Ferdinand, the grandee's amorous son. Ferdinand had just had a brief affair with the daughter of a rich farmer, a rank too far below his own to warrant marriage, and to cool his passion, agreed to visit Cardenio's family. During his stay, Ferdinand made the acquaintance of Lucinda and, much to Cardenio's discomfiture, was very impressed with her charms. At this point in the narrative, the narrator mentions the chivalric book, "Amadis of Gaul," and Don Quixote cannot resist interrupting. Then the youth and the knight begin a heated argument about the virtue of one of the novel's heroines, and Cardenio flings a huge stone at the Don. During the general fight that follows, he disappears into the woods.